Door check



R. V. HARTY DOOR CHECK Dec. 15, 1959 Filed May 4, 1955 2 Sheets-Sheet .1

INVENTOR. Kar/yf; #47u71 BY QW 320%;5

R. V. HARTY DOOR CHECK Dec. 15, 1959 2 Sheets-Sheet 2 Filed May 4, 1955 IN VEN TOR.

United States Patent O 2,916,162 noon CHECK Ralph V. Harty, Detroit, Mich., assignor to v R. V.`Harty Company, Inc.

Application May 4,`1955," Siverial No. 505,905 7'claim`s`. (cnl 16-55) The present invention relates to a door check or door closer for use on swinging or pivoting doors and more 2,916,762 Patented Dec. 15, 1959 vfice of Fig. 1;

specifically 4to a door check vfor commercial use in buildings wherein fork-lift trucks, tractor-drawn trains of small cars, or othervtypes of vehicular and pedestrian traiiic frequently pass inand out, which door check will limit the arc of swinging of the door when pushed open by a person or vehicle, which will close the door when released by the person, truck or other vehicle and which will close the door in such'a fashion as to allow time for the person, truck, or other vehicle to pass throughthe door.

There are numerous typesy of door check mechanisms operated by air, steam or hydraulic pressure which are intended to automatically close a door after traic has passed through. These mechanisms are especially desirable in plants, garages, warehouses, and the like, wherein traic requires frequent opening of heavy and/or wide doors. Most of the mechanisms forthis type of service are subject to many disadvantages such as overhead or exposed mounting where they are likely to be bumped, damaged or subjected'to dirt and they have excessive maintenance costs and highv original cost due -to complicated design.

It is an object of this invention to provide a simple, durable door check easily protected against physical damage and exposure to dirt, etc. j

Another object is to provide a door check of the type described which can be concealed in the oor or overhead structure near the door so as to be protected against physical damage and to have all of its operating mechanism protected against dirt and foreign matter.

Another object is to provide such a door check which employs few parts, which is composed of simple, inexpensive elements, and which is sutliciently rugged to withstand the roughest use.

Yet another object is to provide a door check of the character described which will both hold a swinging door in the closed position and which will close it in a controlled manner.

Still another objectis to provide a door check which will restrain the closure movements of a swinging door and which can be adjusted to regulate the time required for closure `of the door according to the size and character both of the door itself and the nature of the traic in a sealed oil-.filled box disposed :.in the floor. adjacent Fig. 2 is a plan view with portions broken away and in section of the door check of Fig. l, this ligure showing in particular the disposition of the door closing cam, the' follower pin or roller, the follower spring, and the disposition and hookup'of the arrestor dashpot, the sectioned portion being viewed as if along the line '2 2 of Fig. l; and

Fig. 3 is an enlarged elevational view in section of the dashpot itself showing the plunger spools, the sleeve arrangement, the check valve, and the disposition of the ports in the sleeve, the ligure at the left in solid outline showing the plunger withdrawn for purposes of illustration, and at the right in dotted outline at A and B, respectively, the head portion of the plunger in the arresting and release positions relative to the ports in the sleeve-like cylinder.

Referring now to the accompanying drawings, it will be seen that a door 10 is hinged adjacent a. door jamb 12 so ,as to swing about its hinges in both directions. On

each side of the door a substantial metal plate 14 is secured by bolts or the like to the door and the plates 14 are welded to a bearing tube 16. At the bottom of the tube 1-6 a small support plate 18 is welded across the bottom of the plates to afford additional support for thetubej The tube is mounted in a small notch 20 cut in the lower end corner of the door to allow the alignment of the axis of the tube with that of the pins of the door hinges.

Underneath the normal closed position of the door 10, a box 22 formed of metal is recessed into the oor 24. The box '22 is normally illed with oil to a level above the mechanism for a purpose detailed below. A cover 26 ilush withthe oor 24 is provided to seal the box 22 against entrance of dirt and foreign matter. Secured to the bottom of the box is an end-thrust bearing 28 and a second bearing 30 is secured to the cover 26. In the bearings 28, 30 there is journalled a post or shaft 32 having an integral thrust collar 33. The shaft is extended upwardly for mounting in the tube 16 and is secured against rotation therein by a number of pins 34 passed through the tube. Thus mounted, with collar 33 in contactjwith bearing 28, swinging movements of the door 10 result in rotation of shaft 32.

On shaft 32 there is secured, such as by a key or welding, a cam 40 having a shape to be described below. Supported by a bracket 4Z attached to one of the side walls of the box are a pair of plates or levers 44, the levers being pivoted on a pin 46 passed through the bracket 42. In substantially the middle of the levers 44 thereis secured a pin 48. Between the plates the pin 48 carries a collar-like follower roller 49 in rolling contact with thejouter edge of the cam 40. At the free end of the levers 44 there is secured a link 50 which is pivoted in levers 44 on a pin 52. The link 50 could also be a spring clip or any other means of attaching a spring. To the other end of the link 50 there is secured an extension spring 5'4 provided with an eye 56 which connects with a hook-ended or eye-ended screw 58. The threaded end of the screw 58 is passed through a small bracket60 secured below the lower of a pair of dashpot anchor plates 62 secured across the box 22. A wing-nut 64 and lock nut 65 are provided to adjust the tension in the spring 54. The spring 54 resiliently urges the follower roller 49 into contact with the edge of cam 40.

Thecam 40 has secured to its upper face an upstanding pin.70 on which is pivotally secured an end fitting 72 3 of a dashpot plunger 74. The dashpot plunger has a piston-like head 116 tted within a sleeve-like cylinder 76. As will be seen most clearly in Fig. 2, the dashpot extends over to be pivotally secured between the anchor plates 62 by means of a knife blade end fitting 80. The tting Sti is secured on the pin l82 passed through the anchor plates 62. The plates 62, in turn, are rigidly welded between the side walls of the box. Thus mounted, the entire dashpot can pivot about pins 70, 82 as the cam 40 rotates on the shaft 32 so that the dashpot is not subjected to side stresses.

The end of the cylinder`76 adjacent the anchor plates 62 is provided with a welded-on square collar 90 which is secured to yanother similar end collar 92 by pins 94. Between lthe collars 90 and 92 there is secured an outer sleeve 96 forming a closed chamber about the end of cylinder 76, the sleeve 96 being held between the collars 90 and 92 by the pins 94. As seen in Fig. 3, the cylinder 76 is open-ended and does not extend into contact with end collar 92 so that the annular space between cylinder 76 and outer sleeve 96 is in open communication with the open end of sleeve 76.

to force ball 122 off its seat to allow a desired, controlled escape of oil from the space ahead of the piston through the small passageway 12S, thereby allowing the door to continue to move toward the closed position but at a greatly reduced rate. By suitable adjustment of check valve 120 it is possible to obtain considerable variation in the time allowed for a vehicle to clear the doorway and door. When the trailing edge 128 of the spool 112 clears the leading edge of ports 102 (position B, Fig. 3), oil begins to freely escape from the space ahead of the piston head through the annular space, ports 102, along the reduced diameter position 116 and out ports y 100. The plunger is thus released and the door begins At various positions along the length of the cylinder 76 (see Fig. 3) ports or holes are located to allow entry and exit of oil. For example, a first pair of holes or ports 98 is provided in the cylinder near the farthest point of withdrawal of the plunger 74. A second pair of holes or ports 100 is provided in cylinder 76 justoutside the first collar 90 and a third pair 102 is placed just insidel the collar. The first pair of ports 98 provides lubrication of the plunger and insures ease of movement of the plunger during the first portion of its inward travel. The` location of ports 100 determines the point in the swinging arc of the door wherein the swinging of the door `is arrested or greatly slowed to provide time for traffic to pass through lthe doorway. The location of portsf102 likewise determines Vthe position in the arc of the door wherein the door is released to close freely under -the urging of the cam 40. rlhe spacing between the ports 100, 102 will determine the portion of the arc of the door wherein the door will be restrained. The manner in which the dashpot accomplishes this will become clear when the details of the piston head 110 of the plunger 74 are considered.

As will be seen most clearly in Fig. 3, the plunger 74 has an enlarged piston head 110 on which there is provided a rst lland or spool 112 and a second spool 1141 connected thereto by a reduced diameter portion 114.6. An oil groove 115 is provided alongside spool 114. The tail end 117 of the piston lits the cylinder 76 yso as to support the piston head therein. The length of thespools 112, 114 and the length of the reduced diameter portion 116 are designed to cooperate with the ports 100, 102 to provide the desired arresting and release positions. This is seen most clearly in connection with a description of the operation of the dashpot. When the door is wide open in either direction the head 110 of the plunger will be somewhere at the far left of the sleeve 76. As the door starts to close the plunger starts to move to the right in sleeve 76 so that its leading edge 118 clears the first pair of ports 98. In the initial move-y ment of the piston head 110 to the right, oil will be easily displaced( out of ports 98 to reduce the resistance to movement. As spool 112 passes the ports 98 the por tion 1 16 will draw in oil to lubricate the piston head. When the door reaches-a desired intermediate point in its arc the leading edge 118 of spool 112 will close off ports 100 (position A, Fig. 3) and the resistance to rightward movement will suddenly increase due to the rise of pressure within the portion of sleeve 76 enclosed by the outer sleeve 96. Oil trapped ahead of the leading edge 118 then begins to escape from the cvlinder 76 through an adjustable check valve 120 provided in the end plate 92, which valve has a ball 122 seated against a seat 124. An adjustingscrew 126 can be set Aso-'as to close freely ata rate determined by the curvature of cam 40 and the tension in follower spring 54. The leading edge 130 of spool 114 closes or seals ports 100 just' before the piston head reaches its end position to prevent overswinging of the door by a cushioning effect. On its return stroke, ball 122 of check valve 120 is unseated to allow the plunger to move freely so that oil freely enters cylinder 76 and the dashpot does not oppose opening of the door. Engagement of the follower 49 with a detent 132 in the edge of cam 40 brings the door to a stop in the closed position and tends to hold the door in the closed position against the effect of wind, drafts, etc.

The shape of the outer edge 134 of cam 40 is so designed to |`resist opening of the door, and when the door is released, to urge the door back to its closed position. As will be seen most clearly in Fig. 2, the detent 132 in the edge of cam 40 is located on the center line of the cam extending through the follower, the post 32, and the dashpot plunger pivot pin 70. In both directions from V the detent 132 the outeredge 134 of the cam 40 is curved edge of the cam 40 is given a circular curvature to provide ample rotational clearance with respect to the side walls of the box 22. The portions 134 of the outer cam surface, since they are of increasing radius, cause a gradually .increasing pressure to be applied between the surface and follower 49 as the door opens. Thus, the force tending to close the door from either direction increases according to the distance the door is opened and ensures the closing of the door against contrary drafts. The door closes quickly untilthe arresting position A is reached, where the dashpot overcomes the force exerted by cam 40 and its follower 49 and greatly retards the closing movement ofthe door. When the dashpot is at position B it releases the camrand the cam 40 and follower 49 are again effective to close the door the remainder of the way until the detent portion 132 is again engaged by the follower 49.

The door check of this invention is seen to comprise a relatively small number of parts, all of which are 111ggedly built and, since they can'be suspended or operated in oil, are of extremely long life. There is only one valve employed, and this is of a simple, reliable type not easily put out of order. There are no complicated seals, packing Ior external piping or lev'ers'requiring maintenance or periodic replacement. As a result, the door check will operate for long periods of use under rigorous conditions and without requiring attention.

What' is claimed is:

l. A door check compris'ng ashaft,'a'cam connected to said shaft for rotation therewith and havinga curved cam lobe which increases in radiusw-ith respect to the rotational center of said cam and with respect to a direction of rotationof said -cam,.a cam follower. meansresiliently mounted so as to contact said cam lobe, a fluid-operated dashpot pivotally secured to said cam on one end and adapted to be pivotally anchored on its other end, said dashpot having a plunger and a piston head on said r plunger fitted within a cylinder, said piston head having two spaced-apart spools in intimate contact with said cylinder and a reduced diameter portion between said spools, an outer sleeve enclosing a portion of the cylinder and forming an annular outer chamber therewith having an open communication with the interior of said cylinder ahead of said piston head, a pair of ports in said cylinder, a first one of said pair of ports being located exteriorly of said outer sleeve and the second one of said pair of ports being located interiorly of said outer sleeve and communicating with said annular chamber, and a check valve arranged to permit free flow o-f fluid into said cylinder and annular chamber and to restrict flow therefrom, the spacing and location of said ports and said piston head spools being arranged to oppose rotating door closure movements of said cam when a first of said spools closes the first one of said ports while fluid escapes from said cylinder at a controlled rate through said check valve and to release said cam when the first of said spools is moved past the second one of said ports to place the interior of said cylinder in open communication with said second port for escape of fluid through said annular charnber, said second port, along said reduced diameter piston head portion and out said first port, and means for supplying fluid to said first dashpot port and check valve.

2. A door check as defined in claim 1 wherein the means for supplying fluid to said dashpot is an oil-filled enclosure and said dashpot check valve and said first port are in communication with the oil in said enclosure.

3. A door check as defined in claim 1 wherein said cam has a pair of said curved lobes which are interconnected, each of said lobes having al camming surface shaped so as to increase in radius with respect to said shaft in one of the rotational directions of said cam and the said lobes being shaped to correspond, respectively, to opposite rotational directions of said cam, said cam follower is provided with a means for adjusting the force exerted between it and said lobes, and said check 4valve is adjustable so as to control the rate of escape of fluid from said dashpot.

4. A door check comprising a shaft, a cam secured on said shaft for rotation therewith and having a pair of curved cam lobes extending in either rotational direction from a central portion of said cam, said lobes having radii which increase, with respect to the rotational center of said cam, in opposite directions of rotation of said cam, a lever having an anchored end and a free end, a cam follower secured to said lever so as to contact one of said lobes on rotation of said shaft in either direction, adjustable spring means connected to said lever so as to resiliently urge said follower into contact with said lobes, and a dashpot pivotally secured at its one end to said cam and having its other end pivotally anchored so as to be actuated by rotation of said cam in both directions, the said ca m lobes and said follower being adapted normally to cooperate to rotate said shaft toward a position in which said follower engages said cam central portion and said dashpot being adapted to control the time required for rotation of the shaft to said position.

5. A door check as defined in claim 4 wherein a detent-like hollow is provided at said central portion between said cam lobes.

6. A door check for a door adapted to swing about a fixed axis comprising a shaft adapted to be fixedly mounted in said door in alignment with said fixed axis, a cam secured to said shaft so as to rotate as said door swings, said cam having a surface provided with a detent portion corresponding to the closed position of said door,

a curved cam lobe, extending in each rotational direction from said detent, of a radius which increases in a direction of rotation, with respect to the rotational axis of said cam, and a door stop portion of opposite curvature at the end of each said curved lobe corresponding to the desired wide open position of the door, a cam follower element resiliently urged into contact with said cam lobes with sutcient force to tend to return said cam to its closed door position, a dashpot pivotally secured to said cam on one end and pivotally anchored on its other end so as to be actuated by rotation of said cam, said dashpot comprising a plunger pivoted on said cam and having a piston head portion, a cylinder enclosing said head portion, an outer sleeve spaced from and enclosing a portion of the length of said cylinder near the anchored end of said dashpot and in open communication with the said cylinder, a pair of ports in said cylinder, a first one of said pair of ports opening exteriorly of said outer sleeve and the second one of said pair of ports opening interiorly of said outer sleeve, an adjustable check valve communicating with the cylinder4 and the space dened between said sleeve and said cylinder, and a pair of spaced-apart spools on said piston head portion of said plunger and a reduced diameter portion between said spools, the location and spacing of said pair of cylinder ports and the spacing of saidplunger spools on said piston head being adapted to arrest the closing swing of said door at a desired portion of its arc by closure of the first one of said ports by the first of said spools while oil escapes at a controlled rate through said check valve and to release the door when the first of said spools is moved past the second one of said ports to a position between the anchored end of said dashpot and the second one of said ports permitting escape of oil from the cylinder through said outer sleeve, through said second port, along said reduced diameter portion of said piston head and out of the said cylinder through the first one of said ports.

7. A dashpot comprising a plunger, a piston head on said plunger, a cylinder to receive said piston head, said piston head having a pair of spaced-apart spools in contact with said cylinder and a reduced diameter portion between said spools, an outer sleeve enclosing a portion of the length of said cylinder and defining a sealed annular chamber therewith in open communication with the interior of said cylinder, a first port in said cylinder opening exteriorly of said cylinder, a second port in said cylinder spaced from said first port and opening into said annular chamber, and an adjustable valve means arranged to permit free flow of fluid into said sleeve-enclosed portion of said cylinder and said chamber and to restrict flow thereout, said first and second cylinder ports being so spaced and adapted to cooperate with said spools on said piston head as to slow the movement of the plunger, When a first one of said spools closes the said first cylinder port, to a rate determined by said valve means, and to release the said plunger when said first spool moves past said second cylinder port to Permit free escape of uid from said cylinder through said annular chamber, said second port, along said reduced diameter piston head portion and out said first cylinder port.

References Cited in the le of this patent UNITED STATES PATENTS 455,649 Adams July 7, 1891 2,468,410 Schacht Apr. 26, 1949 2,752,627 Carlson July 3, 1956 FOREIGN PATENTS 536,268 Great Britain May 8, 1941 538,942 Great Britain Aug. 22, 1941 679,354 reat Britain Sept. 17, 1952 

